The pair were offered new deals on reduced wages three weeks ago along with Jamie Proctor and Mike Jones.

Proctor has informed Crawley he will not be signing while Jones is also expected to move on but midfielder Bulman and left-back Sadler are still weighing up their options.

Gregory is keen to keep the pair who were key members of Crawley’s side last season but has warned they must make up their minds in the next ten days.

Gregory said: “I hope one or two of the boys who haven’t signed will come back and commit themselves to Crawley for another year.

“Jamie has turned down our offer and I don’t think Mike will stay there is still a chance with Dannie and Matt as they are what I would consider local boys.

“I’m hoping something might happen with those two but I can’t sit and wait forever. They have got to the end of the month really to make up their minds but if I see somebody else I want in their position I will sign them or I might lose them.”

Gregory is also keen to bring wingers Gwion Edwards and Jeffrey Monakana back to Crawley after they impressed on loan at the end of last season.

Reds are in talks with Swansea about signing Edwards – who scored for Wales Under-21s against England on Monday night – on a year-long loan and are monitoring the situation of Monakana at Albion.

Gregory added: “I love Gwion to bits and I’m hopeful he will come back. We are continuing to talk to Swansea but now Gary Monk (manager) has got the job permanently he might want to take a look at Gwion in pre-season first before deciding what to do.

“The door is not closed on that one and I’d also like to get Jeffrey in and have six weeks of pre-season with him. The fact Brighton are in the process of finding a new manager might complicate things a bit but Dave Burke (head of football operations) is in control of players down there and he might be quite happy to let Jeffrey come so we need to have that conversation.”